Radium Audio has released Radium 1.9.37 for Windows and Linux, and Radium 1.9.30 for OS X. Radium is a music editor with a new type of interface. It's inspired by trackers, but has fewer limitations and uses graphics to show musical data.

Features:

Open Source. Radium will never disappear.

Plug-ins:

LADSPA and VST + several built-in plugins:

20 Physical modelling instruments.

2 Soundfont instruments.

1 Sampler instrument.

High quality multiband compressor, reverb and limiter.

More than 100 LADSPA effect plugins are included. (OS X and Windows).

All Sound Objects have built-in high quality filters and equalizers.

Modular mixer. Notes, velocities, pitch and audio signals can be routed to any other audio object.

The "Radium Compressor" (unique interface) built into all instruments.